Need help setting up a >< IF formula in Excel,

[Guest]

This is what I think the formula should read:
=IF(K18<SUM(k87+110)>SUM(K87+90),SUM(K18+800),"")
Excel doesn't agree. I'm trying to say that K18 is an entry cell and if
that value falls between K98+100 (+/-10) that the result will add 800 to K18.
If it falls outside of the +/- range, then the value will return blank.
Help please!

 

[Bob Phillips]

The SUM is superfluous, + makes it add

=IF(AND(K18<K87+110,K18>K87+90),K18+800,"")

 

[Dana DeLouis]

Maybe just another option...

=IF(ABS(K18-K87-100)<10,K18+800,"")

HTH